Project Summary/Abstract Congenital human cytomegalovirus (HCMV) represents the most common viral infection acquired by the developing fetus. Although most infants infected in-utero do not suffer long term symptoms, approximately 10% can have long term sequelae. Central nervous system (CNS) damage is the singular cause of these long term sequelae. Prevention of CNS infection and disease is the target of current antiviral treatment and has been proposed as a goal of prophylactic vaccines. The pathogenesis of CNS disease in congenitally infected human infants remains undefined and to date studies in animal models of CNS infection by HCMV have provided little information secondary to significant limitations inherent in these models. We have recently developed a murine model of infection of the developing CNS with the related murine CMV that recapitulates many key characteristics of the human disease, including hearing loss that is common in infants with congenital CMV infections. Using this model we propose to define mechanisms of protective antibodies that limit CNS infection and disease. In addition, we will explore the use of engineered viruses that are attenuated in their capacity to cause CNS disease and establish persistent infection to induce protective antibody responses. We anticipate that these studies will identify strategies for development of targeted biologics such as antibodies and attenuated viruses that can provide immunologically mediated protection from CNS infection and damage that can follow congenital HCMV infection. Because of the relatedness between MCMV and HCMV, these strategies could be rapidly transitioned into development of similar biologics for human use.